A display device may adopt different types of display panels, such as an organic light emitting diode (OLED) panel or a thin film transistor liquid crystal display (TFT-LCD) panel. A constituent part of the display panel, i.e., the array substrate will be explained below with a TFT-LCD as an example.
A TFT-LCD is generally formed by cell-assembling an array substrate and a color filter substrate. In the array substrate, gate lines and data lines intersect each other to define pixel areas each configured with a pixel electrode and a thin film transistor. The color filter substrate is configured with a black matrix and color filter layers corresponding to pixel areas. The array substrate is configured with common electrode lines. Liquid crystal is filled between the array substrate and the color filter substrate. Driving signals and data signals (voltages of pixel electrodes) are applied to form an electric field that controls rotation of liquid crystal so as to control magnitude of light, which is combined with the color filtering function of the color filter substrate to enable the display panel to display images intended to be expressed.